Published: Dec. 14, 2020 By

Recycling is an essential pillar of a zero-waste lifestyle. It is virtually impossible in our society not to use cardboard, glass, recyclable plastics, etc. With this material already created and a part of the Earth, it is key to close the waste loop by recycling waste and creating something new rather than creating more material to be put into landfills. One contaminant in a recycling bin can ruin an entire batch of recyclable material. Make sure you know these common contaminants to make sure you are recycling properly. 

The Most Common Recycling Contaminants

Food waste

  • This includes unrinsed containers or cardboard with food remains on it. 

Plastic Bags

  • This includes bubble wrap and shrink wrap
  • Some grocery stores recycle their plastic bags, but you have to drop them off there. 

The wrong plastics

Shredded paper

  • Small pieces of paper can cause issues during the recycling process
  • On the CU Campus, you can recycle shredded paper by putting it in a clear plastic bag first before placing it in your paper recycling bin.
  • Off campus, you should compost your shredded paper.

Beverage containers

  • To-go coffee cups and many other beverage containers are not recyclable unless labelled otherwise. 
  • Read the packaging and look it up online to see if it’s recyclable in your local recycling system.
  • Empty all liquids out of your containers.
  • If plastic, screw caps and lids back on these containers
  • If glass, separate the lid from the glass and put them both in the recycling

Frozen food boxes

  • Most frozen food boxes are soaked with a “chemical wet strength” to prevent freezer burn and protect the food during shipping, making them non recyclable (unless specified otherwise on the packaging).

Hazardous waste

  • Paint, cleaning, pesticide, or other hazardous waste containers must be disposed of safely and NOT in your normal recycling/trash/compost bins
  • Check with your local Household Hazardous Waste disposal so you don’t contaminate waste and water systems with toxic materials.

CU Boulder List of Acceptable Materials

Check out this list for more details

Why Contamination Matters

Sorting equipment complications

  • Contaminants like plastic bags get caught in axles of sorting machines that are dangerous and costly to workers that have to remove them.

Unsafe conditions for sorters

  • Workers that sort recycling can be exposed to hazardous material if toxic materials are disposed of incorrectly 

More contamination = less value of recycling

  • A huge part of recycling is the value of the material. Contamination causes less sellable material and less value to recycling. 
  • Contamination down grades materials… ex: if you have too much food coating a piece of paper, it cannot be turned back into paper and either gets turned into toilet paper or sent to the landfill

Recycling is a business

  • It costs money to separate contaminants out of recycling facilities
  • When there are too many contaminants among recyclable material, it is more cost-effective to throw the whole batch into the landfill.



 Help save the recycling industry by keeping your recyclable material clean and separated! 

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